The Molecular Ecology of the Extinct New Zealand Huia

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Abstract

The extinct Huia (Heteralocha acutirostris) of New Zealand represents the most extreme example of beak dimorphism known
in birds. We used a combination of nuclear genotyping methods, molecular sexing, and morphometric analyses of museum
specimens collected in the late 19th and early 20th centuries to quantify the sexual dimorphism and population structure of
this extraordinary species. We report that the classical description of Huia as having distinctive sex-linked morphologies is
not universally correct. Four Huia, sexed as females had short beaks and, on this basis, were indistinguishable from males.
Hence, we suggest it is likely that Huia males and females were indistinguishable as juveniles and that the well-known beak
dimorphism is the result of differential beak growth rates in males and females. Furthermore, we tested the prediction that
the social organisation and limited powers of flight of Huia resulted in high levels of population genetic structure. Using a
suite of microsatellite DNA loci, we report high levels of genetic diversity in Huia, and we detected no significant population
genetic structure. In addition, using mitochondrial hypervariable region sequences, and likely mutation rates and
generation times, we estimated that the census population size of Huia was moderately high. We conclude that the social
organization and limited powers of flight did not result in a highly structured population.

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Rights

2009 Lambert et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Publisher

PLoS One

Description

Funding: This research was supported by Griffith University, the Marsden Fund and the Allan Wilson Centre for Molecular Ecology and Evolution. The funders
had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.